Impossible to get a simple SIM swap

I was hijacked and my phone was ******. All i need to do is have my SIM swapped so i can start to put my life back together again as all my important OTP's etc. are on the old number. No one at MTN can help me, I have spoken with 11 different people so far and all they do is transfer me. Four stores, over 60 minutes on the phone, and still i cant do anything. What now?